Research indicates that permeability of asphalt concrete plays a significant role in performance, particularly in the presence of water. For example, if asphalt concrete is conditioned by water saturation followed by freezing and thawing the retained strength or modulus is typically somewhat lower than for the original dry mixture.
Most asphalt pavements in the United States have an average of about 5-10% air voids. Sufficient of these voids are connected to provide some permeability, but not sufficient permeability for free drainage. Hence, water is commonly trapped within the asphalt concrete and has a deleterious effect, particularly when the concrete is subjected to wide temperature ranges and heavy vehicular traffic. Thus there has been a need for practical and effective asphalt concrete testing system in which compacted bituminous specimens could be water conditioned while selectively temperature conditioned and load conditioned. The present invention aims to fill this need so that the best performing asphalt concrete mixture for a given location can be more accurately selected.